Unauthenticated Denial of Service in MongoDB Server via Assertion Failure in Read Concern Processing on Replica Set Members

A security issue in MongoDB Server allows an unauthenticated network user to cause a denial of service on a specific type of replica set member. The server contains an assertion in its read concern processing logic that can be reached without authentication, and the assertion's assumptions about internal state do not hold for all member configurations, causing the server process to terminate.